Pumps are generally used to transport fluids at a desired flow and pressure from one location to another or, alternatively, to recirculate fluid in a system. Examples of such applications include, but are not limited to: oil wells, gas wells, water wells, irrigation systems, heating and cooling systems, wastewater treatment systems, municipal water treatment systems, distribution systems, and the like. Various operating parameters of the pump may be controlled to protect the pump from damage, optimize operation of the pump, increase pump efficiency, and/or increase fluid production. Examples of pump operating parameters include, for example, pump speed, pump torque, fluid flow rate, pump input pressure, and pump output pressure.
One or more sensors may be used inside the wellbore or “downhole” to measure pump operating parameters directly. In many applications, the placement required for the sensors is inconvenient or difficult to access and may require that the sensors be exposed to a harmful environment, thereby decreasing system reliability. Additionally, sensor installation and maintenance costs add to the overall cost of the pumping system. Still further, replacing or repairing the sensors may require that pump operations be suspended. Therefore, installation, operation, and maintenance costs may be reduced, and overall pump system productivity and reliability may be improved by eliminating the placement of sensors inside the well.